The invention set forth in this specification pertains to new and improved hand trucks. More specifically it pertains to new and improved hand trucks which are constructed so as to employ wheel units having multiple wheels. The use of such wheel units makes the hand trucks of the present invention especially desirable for use in moving loads both upon a horizontal surface and in moving loads up and down stairs.
Most conventional hand trucks are constructed so as to utilize an elongated, normally vertically extending body or frame carrying at its lower end a toe plate extending from the front of the frame and carrying wheels or wheel means generally at each side of the frame and adjacent to the back of the frame adjacent to the lower end of the frame. Such a hand truck normally includes handles or handle means attached to the frame adjacent to or at the upper end of the frame for use in manipulating the hand truck and, when a load is carried upon it, the hand truck and the load from one location to another. Such conventional hand trucks have been employed for many years in many different applications and are satisfactory for many different uses.
During the normal use of such a conventional hand truck an object or load is located on the toe plate of the hand truck generally adjacent to or against the frame or body and the hand truck is tilted back as it is supported by the handles so that the weight supported by the wheels is reasonably "balanced" relative to the wheels as the hand truck is thereafter moved and/or manipulated. Frequently there is a problem in maintaining such a "balance" with a hand truck. Also on occasion the movement of such a hand truck as, for example, in moving the hand truck up or down a flight of stairs or over a curb can be a significant problem.
As a result of the recognition of such problems a large number of different hand truck constructions have been proposed to facilitate the manipulation and movement of a hand truck in transporting loads both upon vertical surfaces and up and down stairs. It is not considered that an understanding of the present invention requires any sort of a discussion of the various expedients which have been proposed and to various extents used to facilitate the use of a hand truck in moving loads. Many of such expedients have proved reasonably desirable and utilitarian. In spite of this it is considered that there is still a need for new and improved hand trucks for use in moving loads of various different types either along a generally vertical surface or up and down various types of stairs or related structures.